Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 20 2025 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...20z Update... Changes were made to clear the Marginal Risk across portions of central Texas where thunderstorms and outflow have moved southward. The Marginal Risk was expanded across the Southeast into portions of northwest Georgia and eastern Alabama. A cluster of thunderstorms continues to sag southward into this region, with cores exhibiting some uptick in intensity. See MCD#1995. Otherwise, the outlook remains on track with no additional changes needed. See previous discussion below for more information. ..Thornton.. 08/20/2025 .PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Aug 20 2025/ ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0220 PM CDT Wed Aug 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to locally severe thunderstorms are possible Friday from parts of the central and northern High Plains into the Upper Midwest. ...Northern/Central High Plains to Upper Midwest... An upper cyclone over the Canadian Prairies and its attendant trough will develop southeast across portions of the northern/central Plains and Upper Midwest/Great Lakes on Friday. At the surface, a cold front will develop south/southeast across the region. A seasonally moist airmass will be in place near and ahead of the front. A narrow corridor of 1000-3000 J/kg MLCAPE is forecast ahead of the front from the WY/CO High Plains eastward across parts of NE and northeast into southern MN and northern/central WI. Isolated to widely scattered thunderstorms are expected to develop during the afternoon across portions of WI/MN and the U.P. of MI. closer to the surface low over Ontario. Vertical shear is expected to remain modest, with stronger shear likely trailing the cold front. Nevertheless, steepened low-level lapse rates where stronger heating occurs could support sporadic strong to severe gusts. Additional storms are expected to develop in the post-frontal upslope regime across parts of eastern WY and northeast CO during the late afternoon/evening. This activity may eventually become a forward propagating cluster across NE during the nighttime hours as the surface cold front develops southward toward the KS border. Forecast soundings indicated sufficient deep shear and elongated/straight hodographs will be present amid steep midlevel lapse rates. Isolated large hail may be possible initially, with an increasing chance for isolated damaging gusts if sufficient clustering can occur further east into NE and vicinity. ..Leitman.. 08/20/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more